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.\" Copyright 2013 Darik Horn <dajhorn@vanadac.com>. All rights reserved.
.\"
.\" lint-ok: WARNING: sections out of conventional order: Sh SYNOPSIS
.\"
.Dd May 26, 2021
.Dt ZINJECT 8
.Os
.
.Sh NAME
.Nm zinject
.Nd ZFS Fault Injector
.Sh DESCRIPTION
.Nm
creates artificial problems in a ZFS pool by simulating data corruption
or device failures.
This program is dangerous.
.
.Sh SYNOPSIS
.Bl -tag -width Ds
.It Xo
.Nm zinject
.Xc
List injection records.
.
.It Xo
.Nm zinject
.Fl b Ar objset : Ns Ar object : Ns Ar level : Ns Ar start : Ns Ar end
.Op Fl f Ar frequency
.Fl amu
.Op pool
.Xc
Force an error into the pool at a bookmark.
.
.It Xo
.Nm zinject
.Fl c Ar id Ns | Ns Sy all
.Xc
Cancel injection records.
.
.It Xo
.Nm zinject
.Fl d Ar vdev
.Fl A Sy degrade Ns | Ns Sy fault
.Ar pool
.Xc
Force a vdev into the DEGRADED or FAULTED state.
.
.It Xo
.Nm zinject
.Fl d Ar vdev
.Fl D Ar latency : Ns Ar lanes
.Ar pool
.Xc
Add an artificial delay to I/O requests on a particular
device, such that the requests take a minimum of
.Ar latency
milliseconds to complete.
Each delay has an associated number of
.Ar lanes
which defines the number of concurrent
I/O requests that can be processed.
.Pp
For example, with a single lane delay of 10 ms
.No (\& Ns Fl D Ar 10 : Ns Ar 1 ) ,
the device will only be able to service a single I/O request
at a time with each request taking 10 ms to complete.
So, if only a single request is submitted every 10 ms, the
average latency will be 10 ms; but if more than one request
is submitted every 10 ms, the average latency will be more
than 10 ms.
.Pp
Similarly, if a delay of 10 ms is specified to have two
lanes
.No (\& Ns Fl D Ar 10 : Ns Ar 2 ) ,
then the device will be able to service
two requests at a time, each with a minimum latency of 10 ms.
So, if two requests are submitted every 10 ms, then
the average latency will be 10 ms; but if more than two
requests are submitted every 10 ms, the average latency
will be more than 10 ms.
.Pp
Also note, these delays are additive.
So two invocations of
.Fl D Ar 10 : Ns Ar 1
are roughly equivalent to a single invocation of
.Fl D Ar 10 : Ns Ar 2 .
This also means, that one can specify multiple
lanes with differing target latencies.
For example, an invocation of
.Fl D Ar 10 : Ns Ar 1
followed by
.Fl D Ar 25 : Ns Ar 2
will create 3 lanes on the device: one lane with a latency
of 10 ms and two lanes with a 25 ms latency.
.
.It Xo
.Nm zinject
.Fl d Ar vdev
.Op Fl e Ar device_error
.Op Fl L Ar label_error
.Op Fl T Ar failure
.Op Fl f Ar frequency
.Op Fl F
.Ar pool
.Xc
Force a vdev error.
.
.It Xo
.Nm zinject
.Fl I
.Op Fl s Ar seconds Ns | Ns Fl g Ar txgs
.Ar pool
.Xc
Simulate a hardware failure that fails to honor a cache flush.
.
.It Xo
.Nm zinject
.Fl p Ar function
.Ar pool
.Xc
Panic inside the specified function.
.
.It Xo
.Nm zinject
.Fl t Sy data
.Fl C Ar dvas
.Op Fl e Ar device_error
.Op Fl f Ar frequency
.Op Fl l Ar level
.Op Fl r Ar range
.Op Fl amq
.Ar path
.Xc
Force an error into the contents of a file.
.
.It Xo
.Nm zinject
.Fl t Sy dnode
.Fl C Ar dvas
.Op Fl e Ar device_error
.Op Fl f Ar frequency
.Op Fl l Ar level
.Op Fl amq
.Ar path
.Xc
Force an error into the metadnode for a file or directory.
.
.It Xo
.Nm zinject
.Fl t Ar mos_type
.Fl C Ar dvas
.Op Fl e Ar device_error
.Op Fl f Ar frequency
.Op Fl l Ar level
.Op Fl r Ar range
.Op Fl amqu
.Ar pool
.Xc
Force an error into the MOS of a pool.
.El
.Sh OPTIONS
.Bl -tag -width "-C dvas"
.It Fl a
Flush the ARC before injection.
.It Fl b Ar objset : Ns Ar object : Ns Ar level : Ns Ar start : Ns Ar end
Force an error into the pool at this bookmark tuple.
Each number is in hexadecimal, and only one block can be specified.
.It Fl C Ar dvas
Inject the given error only into specific DVAs.
The mask should be specified as a list of 0-indexed DVAs separated by commas
.No (e.g . Ar 0,2 Ns No ).
This option is not applicable to logical data errors such as
.Sy decompress
and
.Sy decrypt .
.It Fl d Ar vdev
A vdev specified by path or GUID.
.It Fl e Ar device_error
Specify
.Bl -tag -compact -width "decompress"
.It Sy checksum
for an ECKSUM error,
.It Sy decompress
for a data decompression error,
.It Sy decrypt
for a data decryption error,
.It Sy corrupt
to flip a bit in the data after a read,
.It Sy dtl
for an ECHILD error,
.It Sy io
for an EIO error where reopening the device will succeed, or
.It Sy nxio
for an ENXIO error where reopening the device will fail.
.El
.Pp
For EIO and ENXIO, the "failed" reads or writes still occur.
The probe simply sets the error value reported by the I/O pipeline
so it appears the read or write failed.
Decryption errors only currently work with file data.
.It Fl f Ar frequency
Only inject errors a fraction of the time.
Expressed as a real number percentage between
.Sy 0.0001
and
.Sy 100 .
.It Fl F
Fail faster.
Do fewer checks.
.It Fl f Ar txgs
Run for this many transaction groups before reporting failure.
.It Fl h
Print the usage message.
.It Fl l Ar level
Inject an error at a particular block level.
The default is
.Sy 0 .
.It Fl L Ar label_error
Set the label error region to one of
.Sy nvlist ,
.Sy pad1 ,
.Sy pad2 ,
or
.Sy uber .
.It Fl m
Automatically remount the underlying filesystem.
.It Fl q
Quiet mode.
Only print the handler number added.
.It Fl r Ar range
Inject an error over a particular logical range of an object, which
will be translated to the appropriate blkid range according to the
object's properties.
.It Fl s Ar seconds
Run for this many seconds before reporting failure.
.It Fl T Ar failure
Set the failure type to one of
.Sy all ,
.Sy claim ,
.Sy free ,
.Sy read ,
or
.Sy write .
.It Fl t Ar mos_type
Set this to
.Bl -tag -compact -width "spacemap"
.It Sy mos
for any data in the MOS,
.It Sy mosdir
for an object directory,
.It Sy config
for the pool configuration,
.It Sy bpobj
for the block pointer list,
.It Sy spacemap
for the space map,
.It Sy metaslab
for the metaslab, or
.It Sy errlog
for the persistent error log.
.El
.It Fl u
Unload the pool after injection.
.El
.
.Sh ENVIRONMENT VARIABLES
.Bl -tag -width "ZF"
.It Ev ZFS_HOSTID
Run
.Nm
in debug mode.
.El
.
.Sh SEE ALSO
.Xr zfs 8 ,
.Xr zpool 8
